Brighton must wish that they could play Newcastle every week. The outcome was the same as the one in the fourth round of the FA Cup last season but while this will be painted as a giantkilling by some, the reality was rather different. Newcastle are in a mess, Friday's sale of Demba Ba to Chelsea deepening the gloom and afterwards their manager, Alan Pardew, admitted his main concern was ensuring that they are still in the Premier League next season.

This was a chastening experience for a young Newcastle side, who ended the game with 10 men after Shola Ameobi, stepping in for the injured Fabricio Coloccini as captain, was sent off for two bookings midway through the second half. Coloccini was just one of a number of first-team players who was absent with injury and Cheik Tioté has already joined Ivory Coast for the Africa Cup of Nations. The return of Yohan Cabaye, Hatem Ben Arfa and Papiss Cissé cannot come soon enough, although the arrival of the France right-back, Mathieu Debuchy, from Lille is a rare piece of positive news.

However, he was not signed in time to appear at the Amex Stadium. Instead Newcastle, who have lost nine of their past 11 matches in the league, were forced to rely on youngsters. It is not often that a Premier League side can be viewed as the underdogs when they take on opposition from a division below them in the Cup, but the threadbare nature of Newcastle's squad was reflected by Pardew using the 21-year-old defenders James Tavernier and Paul Dummett, and the 20-year-old Algerian midfielder Mehdi Abeid. Newcastle were simply too callow.

Brighton, who are ninth in the Championship, still had to take advantage of the visitors' weaknesses, though, and at times they were exceptional. Gus Poyet is a manager who is almost dogmatic in his insistence that his teams play free-flowing attacking football that is easy on the eye and they did not let anyone down here. Brighton, particularly in the first half, took Newcastle apart at will with their intelligent, patient but always purposeful approach.

There was disappointment before kick-off that the influential winger, Will Buckley, was only fit enough for a place on the bench after hamstring trouble but it made no difference. Intent on testing Newcastle's ramshackle defence straight away, they could have gone in front after nine minutes when Gary Dicker's stooping header from David López's cross was cleared off the line by James Perch, whom Pardew was frustrated to lose later with a knee injury.

In response, Gaël Bigirimana tested Casper Ankergren with a stinging drive from the edge of the area but Brighton were rarely troubled.

They took the lead after 33 minutes with a beautifully constructed goal. From inside his own half, Gordon Greer found Wayne Bridge with a raking pass that exposed Gabriel Obertan's inability to track back.

The former England left-back reached the ball just before it went behind and managed to knock a cross towards Andrea Orlandi. He could have left it for Craig Mackail-Smith but despite the Spaniard being closely marked with his back to goal, he stunned Newcastle with an outstanding piece of improvisation, hooking a volley with the outside of his left foot past Rob Elliot and into the bottom-left corner.

Newcastle's task became even more difficult when they lost Shola Ameobi, who cut an isolated figure up front, to an unfortunate red card early in the second half.

Not long after picking up a first yellow card for not very much at all, he caught López after 63 minutes. It was a challenge Ameobi did not need to make but the Spanish right-back certainly made the most of it, convincing Lee Probert to reduce Newcastle to 10 men.

"I think it was harsh," Pardew said. "The player didn't help him in any way. He has a little look up at the referee and starts rolling around. It was a nothing foul." He did admit his captain had been naive to make the challenge.

The sending-off prompted a brief revival from Newcastle's youngsters and Sylvain Marveaux and Sammy Ameobi went close as Brighton grew complacent.

Yet just as Newcastle were starting to believe again, Will Hoskins ran through with three minutes left to beat Elliot soundly and seal Brighton's place in the next round.

Newcastle have not made it past the fourth round since 2006 but Pardew has bigger things to worry about now.